Evaluating the Possible Use of High Modulus Asphalt Mixtures in Flexible Pavements in Vietnam

Abstract

Despite of hot climatic conditions and high traffic volume, flexible pavement still covers more than 90% of the road system in Vietnam due to its advantages over rigid pavement, e.g. smoothness for vehicles and ease of construction and repair. Consequently, permanent deformation become a persistent problem to be solved in the country. Attempts have been made to improve the resistance to rutting of asphalt mixtures including the modification of the mixture gradation, bitumen rheology improvement and tight quality control in manufacturing and construction of asphalt concrete (AC). High modulus asphalt concrete (HMAC) has long-time been found good material for preventing rutting distress and improving fatigue life of asphalt pavement. Because the thickness of pavement structures in Vietnam is normally very small (12–15 cm of asphalt) while HMAC is 2–3 times stiffer than conventional AC, there is still concern about the fatigue life of pavement structures comprised of HMAC. The aim of this study is to analyse the maximal tensile stress and strain occurring in thin asphalt pavement structures comprised of one or two layers of HMAC and (or) conventional AC and predict their fatigue lives. It was shown that using HMAC properly will increase the bottom-up fatigue life of the pavement. Thus, it is possible to use HMAC in thin asphalt pavement structures like those in Vietnam for preventing rutting distress without concerns about cracking.